Chronic pain is a serious health issue, affecting millions of people around the world. Some of the most powerful analgesics are opioids, which are not ideal for chronic use due to maladaptive responses, such as abuse and tolerance. Agmatine has been shown to reduce both chronic pain behaviors and opioid-induced neuroplasticity. However, systemic administration of agmatine may demonstrate limited central nervous system penetrance due to its polar character. Therefore, we have developed a series of strategically substituted agmatines (SSAs) to increase the lipophilicity of agmatine and potentially improve the distribution across the blood brain barrier. The goal of this study is to compare one of these compounds, SSA3, to agmatine with regards to pharmacokinetics and pharmacodynamics. Our hypothesis is that SSAs exhibit similar pharmacological action as agmatine at lower doses, with an improved pharmacokinetic profile. Following development of a novel LC-MS/MS protocol for quantification of SSA3 in plasma, we analyzed the pharmacokinetics in rat plasma using serial sampling via jugular catheter. All in vivo experiments were reviewed and approved by the University of Minnesota IACUC and the ACURO of the Department of Defense. After intravenous administration, SSA3 showed a 44±7 min elimination half-life. This half-life is increased compared to agmatine, with a reported elimination half-life of 7 min. Neither clearance nor volume of distribution were dose-dependent at the studied doses, determined as 0.37±0.04 L/min/kg and 21±3 L/kg, respectively. After oral administration, a similar elimination half-life is seen, suggesting no alteration in elimination based on route of administration. The oral bioavailability determined based on area under the curve is 13.1%. To assess the impact of SSA3 on neuropathic pain, SSA3 was administered to rats with spared nerve injury, and the tactile hypersensitivity was assessed using the von Frey monofilament stimulation. Intravenous SSA3 was able to reduce tactile hypersensitivity in injured rats at lower doses than agmatine and increased the duration of reversal at similar doses. SSA3 shows increased distribution and slower elimination as compared to agmatine, serving as a potential explanation for the increased action in nerve-injured animals. In conclusion, alterations in the chemical structure to the parent compound appears to have conferred enhanced biopharmaceutical features accounting for improved pharmacological parameters.